This invention relates to improvements in the process of partial oxidation of petroleum feedstocks to produce synthesis gas and related products therefrom. In particular, the improvements relate to the recovery of unreacted carbon and temperature moderation of the reactor used to produce the synthesis gas.
The oxygen-blown partial oxidation of petroleum feedstocks requires the addition of a tempering medium such as steam to keep the reactor temperature within certain permissible limits. These limits are set by the economy of operation and the temperature restrictions of the reactor refractory material. Past practice has been to inject high pressure superheated steam into the petroleum feedstock charged to the partial oxidation generator. This practice is effective but usually requires either a waste heat recovery apparatus or a supply of clean, non-polluting fuel to operate a special boiler used to produce the tempering steam. These requirements add to the cost of the equipment utilized in the process, attendant maintenance costs and energy requirements.
A problem connected with the process is handling the unconverted or unreacted carbon. Normally the carbon is scrubbed from the reactor gaseous effluent with water resulting in a water and/or oil slurry which is thereafter contacted with petroleum naphtha. The naphtha preferentially wets the carbon and separates the carbon from the water stream. The carbon may then be transferred to a heavy oil stream by mixing heavy oil with the naphtha. The heavy fraction from the distillation process contains substantially all of the unreacted carbon which can be used as the feedstock for the partial oxidation reactor thus completely utilizing the carbon contained in the oil charge to produce a useful product. The process briefly described above requires a substantial amount of equipment and energy to separate and recycle the carbon.